Initial firmware commit.

firmware/baseband/dsp_demodulate.hpp

@@ -0,0 +1,66 @@
+/*
+ * Copyright (C) 2014 Jared Boone, ShareBrained Technology, Inc.
+ *
+ * This file is part of PortaPack.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifndef __DSP_DEMODULATE_H__
+#define __DSP_DEMODULATE_H__
+
+#include "dsp_types.hpp"
+
+namespace dsp {
+namespace demodulate {
+
+class AM {
+public:
+	buffer_s16_t execute(
+		buffer_c16_t src,
+		buffer_s16_t dst
+	);
+};
+
+class FM {
+public:
+	/*
+	 * angle: -pi to pi. output range: -32768 to 32767.
+	 * Maximum delta-theta (output of atan2) at maximum deviation frequency:
+	 * delta_theta_max = 2 * pi * deviation / sampling_rate
+	 */
+	constexpr FM(
+		const float sampling_rate,
+		const float deviation_hz
+	) : z_ { 0 },
+		k { static_cast<float>(32767.0f / (2.0 * pi * deviation_hz / sampling_rate)) }
+	{
+	}
+
+	buffer_s16_t execute(
+		buffer_c16_t src,
+		buffer_s16_t dst
+	);
+
+private:
+	complex16_t::rep_type z_;
+	const float k;
+};
+
+} /* namespace demodulate */
+} /* namespace dsp */
+
+#endif/*__DSP_DEMODULATE_H__*/